In conclusion, although spinal gangliogliomas display histologic and clinical features similar to their supratentorial counterparts, they show a relatively low frequency of BRAF(V600E) mutations, alteration otherwise common in hemispheric and brain stem gangliogliomas.
To identify potential molecular features predictive of brainstem ganglioglioma's clinical outcomes, a retrospective cohort of 28 World Health Organization (WHO) grade I brainstem gangliogliomas was analysed for BRAFV600E, IDH1 R132H, and IDH2 R172K mutations, TERT C228T/C250T promoter mutation, H3F3A K27M mutation and MGMT methylation.
Our study shows that cellular polymorphism in PAs and gangliogliomas does not affect the results of molecular analysis investigating the status of the KIAA1549-BRAF fusion gene.
While v-Raf murine sarcoma viral oncogene homolog B (BRAF) mutation is found in up to 50% of pediatric gangliogliomas, two recent studies found that it was rare in DIA/DIGs; we sought to assess BRAF status in DIA/DIGs from our institution.
An extensive literature search revealed that our patient is the fourth case of pigmented ganglioglioma described in the literature and was positive for BRAFV600E mutation by molecular studies.
Here, we show that the oncogenic BRAF somatic mutation p.Val600Glu (V600E) in developing neurons underlies intrinsic epileptogenicity in ganglioglioma, one of the leading causes of intractable epilepsy<sup>2</sup>.
In both GGs and DNTs, the presence of BRAFV600E mutation was significantly associated with the expression of CD34, phosphorylated ribosomal S6 protein (pS6; marker of mTOR pathway activation) in dysplastic neurons and synaptophysin (P < 0.05).
We describe a case of an adult with a progressive <i>BRAF V600E</i> mutant spinal cord ganglioglioma 9 years after surgery who was treated with vemurafenib.
BRAF mutations are most frequently detected in certain subtypes of low-grade glioma, such as pilocytic astrocytoma (PA), pleomorphic xanthoastrocytoma (PXA), ganglioglioma (GG) and dysembryoplastic neuroepithelial tumor (DNT).
Activation of the MAP Kinase (MAPK) pathway caused by the BRAFV600E mutation or the KIAA1549-BRAF fusion has been reported in pediatric GG and PA, respectively.
BRAFV600E mutation, a genetic abnormality seen in a significant percentage of pleomorphic xanthoastrocytomas and GGs, was assessed by polymerase chain reaction and identified in the tumor.
As co-occurrence of H3 K27M and BRAFV600E mutations has been reported in midline tumors and anaplastic GG, we searched for BRAF V600E and H3 K27M mutations in a series of 54 paediatric midline grade I GG (midline GG) to determine the frequency of double mutations and its relevance for prognosis.
Importantly, this case contradicts previous reports of p53 and BRAF mutations portending worsened tumor behavior and prognosis and demonstrates that further studies are needed to delineate the role of genetic characterization in the biologic understanding and management of gangliogliomas.
No significant differences regarding additional imaging features emerged between BRAFV600E-mutant and wild-type lesions, with the exception of the number of tumors with cystic components, significantly higher in BRAFV600E-mutant PAs (p = 0.011) CONCLUSION: Assessment of the DWI characteristics of GGs and PAs may assist in predicting BRAF V600E status, suggesting a radiogenomic correlation and prompt molecular characterization of these tumors.
The highest frequencies of BRAF (V600E) mutations were found in WHO grade II pleomorphic xanthoastrocytomas (42/64; 66%) and pleomorphic xanthoastrocytomas with anaplasia (15/23; 65%), as well as WHO grade I gangliogliomas (14/77; 18%), WHO grade III anaplastic gangliogliomas (3/6) and pilocytic astrocytomas (9/97; 9%).
In the third case, where the interval spanned multiple decades, the GG was found to be positive for both BRAFp.V600E immunohistochemistry (IHC) and for the KIAA1549-BRAF fusion.